package cli

import (
	"context"
	"fmt"
	"io"
	"strconv"
	"strings"
	"time"

	"github.com/Gitlawb/zero/internal/config"
	"github.com/Gitlawb/zero/internal/redaction"
	"github.com/Gitlawb/zero/internal/selfverify"
	"github.com/Gitlawb/zero/internal/testrunner"
	"github.com/Gitlawb/zero/internal/verify"
	"github.com/Gitlawb/zero/internal/worktrees"
	"github.com/Gitlawb/zero/internal/zerogit"
	"github.com/Gitlawb/zero/internal/zeroruntime"
)

type worktreeCommandOptions struct {
	json    bool
	name    string
	baseDir string
	cwd     string
}

type verifyCommandOptions struct {
	json      bool
	cwd       string
	only      []string
	timeoutMS int
	attempts  int
}

type changesCommandOptions struct {
	json         bool
	cwd          string
	baseRef      string
	message      string
	hasMessage   bool
	dryRun       bool
	maxDiffBytes int
	auto         bool
}

func runWorktrees(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) int {
	command := "prepare"
	if len(args) > 0 && !strings.HasPrefix(args[0], "-") {
		command = strings.ToLower(strings.TrimSpace(args[0]))
		args = args[1:]
	}
	if command == "help" {
		if err := writeWorktreesHelp(stdout); err != nil {
			return exitCrash
		}
		return exitSuccess
	}
	if command != "prepare" {
		return writeExecUsageError(stderr, fmt.Sprintf("unknown worktrees command %q", command))
	}
	options, help, err := parseWorktreeCommandArgs(args)
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	if help {
		if err := writeWorktreesHelp(stdout); err != nil {
			return exitCrash
		}
		return exitSuccess
	}
	workspaceRoot, err := resolveWorkspaceRoot(options.cwd, deps)
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	result, err := deps.prepareWorktree(context.Background(), worktrees.Options{
		Cwd:     workspaceRoot,
		Name:    options.name,
		BaseDir: options.baseDir,
		Now:     deps.now,
	})
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	safeResult := redactWorktreeResult(result)
	if options.json {
		if err := writePrettyJSON(stdout, safeResult); err != nil {
			return exitCrash
		}
		return exitSuccess
	}
	if _, err := fmt.Fprintln(stdout, formatWorktreeResult(safeResult)); err != nil {
		return exitCrash
	}
	return exitSuccess
}

func runVerifyCommand(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) int {
	options, help, err := parseVerifyCommandArgs(args)
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	if help {
		if err := writeVerifyHelp(stdout); err != nil {
			return exitCrash
		}
		return exitSuccess
	}
	workspaceRoot, err := resolveWorkspaceRoot(options.cwd, deps)
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	plan, err := deps.detectVerifyPlan(workspaceRoot)
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	if options.attempts > 1 {
		loopReport := deps.runSelfVerify(context.Background(), plan, selfverify.Options{
			RunOptions: verify.RunOptions{
				Only:      options.only,
				TimeoutMS: options.timeoutMS,
				Now:       deps.now,
			},
			MaxAttempts: options.attempts,
		})
		safeLoopReport := redactVerifyLoopReport(loopReport)
		if options.json {
			if err := writePrettyJSON(stdout, selfverify.SnapshotFromReport(safeLoopReport)); err != nil {
				return exitCrash
			}
		} else if _, err := fmt.Fprintln(stdout, formatVerifyLoopReport(safeLoopReport)); err != nil {
			return exitCrash
		}
		if !loopReport.OK {
			return exitProvider
		}
		return exitSuccess
	}
	report := deps.runVerify(context.Background(), plan, verify.RunOptions{
		Only:      options.only,
		TimeoutMS: options.timeoutMS,
		Now:       deps.now,
	})
	safeReport := redactVerifyReport(report)
	if options.json {
		if err := writePrettyJSON(stdout, verify.SnapshotFromReport(safeReport)); err != nil {
			return exitCrash
		}
	} else if _, err := fmt.Fprintln(stdout, formatVerifyReport(safeReport)); err != nil {
		return exitCrash
	}
	if !report.OK {
		return exitProvider
	}
	return exitSuccess
}

func runChanges(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) int {
	command := "inspect"
	if len(args) > 0 && !strings.HasPrefix(args[0], "-") {
		command = strings.ToLower(strings.TrimSpace(args[0]))
		args = args[1:]
	}
	if command == "help" {
		if err := writeChangesHelp(stdout); err != nil {
			return exitCrash
		}
		return exitSuccess
	}
	options, help, err := parseChangesArgs(args, command)
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	if help {
		if err := writeChangesHelp(stdout); err != nil {
			return exitCrash
		}
		return exitSuccess
	}
	workspaceRoot, err := resolveWorkspaceRoot(options.cwd, deps)
	if err != nil {
		return writeExecUsageError(stderr, err.Error())
	}
	switch command {
	case "inspect", "status":
		summary, err := deps.inspectChanges(context.Background(), zerogit.InspectOptions{
			Cwd:          workspaceRoot,
			BaseRef:      options.baseRef,
			MaxDiffBytes: options.maxDiffBytes,
		})
		if err != nil {
			return writeExecUsageError(stderr, err.Error())
		}
		safeSummary := redactChangeSummary(summary)
		if options.json {
			if err := writePrettyJSON(stdout, zerogit.SnapshotFromSummary(safeSummary)); err != nil {
				return exitCrash
			}
			return exitSuccess
		}
		if _, err := fmt.Fprintln(stdout, formatChangeSummary(safeSummary)); err != nil {
			return exitCrash
		}
		return exitSuccess
	case "commit":
		var message string
		if options.auto {
			summary, err := deps.inspectChanges(context.Background(), zerogit.InspectOptions{
				Cwd:          workspaceRoot,
				MaxDiffBytes: options.maxDiffBytes,
			})
			if err != nil {
				return writeExecUsageError(stderr, fmt.Sprintf("failed to inspect changes: %v", err))
			}
			if summary.Clean {
				return writeExecUsageError(stderr, "no changes to commit")
			}

			resolved, err := deps.resolveConfig(workspaceRoot, config.Overrides{})
			if err != nil {
				return writeExecUsageError(stderr, fmt.Sprintf("failed to resolve config: %v", err))
			}
			if !config.HasProviderProfile(resolved.Provider) {
				return writeExecUsageError(stderr, "no provider configured for auto-commit message")
			}
			provider, err := deps.newProvider(resolved.Provider)
			if err != nil {
				return writeExecUsageError(stderr, fmt.Sprintf("failed to create provider: %v", err))
			}

			if !options.json {
				if _, err := fmt.Fprintln(stdout, "Generating commit message using LLM..."); err != nil {
					return exitCrash
				}
			}

			safeSummary := redactChangeSummary(summary)
			genCtx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
			defer cancel()
			msg, err := generateAutoCommitMessage(genCtx, provider, resolved.Provider.Model, safeSummary)
			if err != nil {
				return writeExecUsageError(stderr, fmt.Sprintf("failed to generate commit message: %v", err))
			}
			message = msg
		} else {
			message = options.message
		}

		result, err := deps.commitChanges(context.Background(), zerogit.CommitOptions{
			Cwd:          workspaceRoot,
			Message:      message,
			DryRun:       options.dryRun,
			MaxDiffBytes: options.maxDiffBytes,
		})
		if err != nil {
			return writeExecUsageError(stderr, err.Error())
		}
		safeResult := redactCommitResult(result)
		if options.json {
			if err := writePrettyJSON(stdout, safeResult); err != nil {
				return exitCrash
			}
			return exitSuccess
		}
		if _, err := fmt.Fprintln(stdout, formatCommitResult(safeResult)); err != nil {
			return exitCrash
		}
		return exitSuccess
	default:
		return writeExecUsageError(stderr, fmt.Sprintf("unknown changes command %q", command))
	}
}

func parseWorktreeCommandArgs(args []string) (worktreeCommandOptions, bool, error) {
	options := worktreeCommandOptions{}
	for index := 0; index < len(args); index++ {
		arg := args[index]
		switch {
		case arg == "-h" || arg == "--help" || arg == "help":
			return options, true, nil
		case arg == "--json":
			options.json = true
		case arg == "--name":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			if err := setWorktreeName(&options, value); err != nil {
				return options, false, err
			}
			index = next
		case strings.HasPrefix(arg, "--name="):
			if err := setWorktreeName(&options, strings.TrimPrefix(arg, "--name=")); err != nil {
				return options, false, err
			}
		case arg == "--dir":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			options.baseDir = value
			index = next
		case strings.HasPrefix(arg, "--dir="):
			options.baseDir = strings.TrimSpace(strings.TrimPrefix(arg, "--dir="))
		case arg == "-C" || arg == "--cwd":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			options.cwd = value
			index = next
		case strings.HasPrefix(arg, "--cwd="):
			options.cwd = strings.TrimSpace(strings.TrimPrefix(arg, "--cwd="))
		case strings.HasPrefix(arg, "-"):
			return options, false, execUsageError{fmt.Sprintf("unknown worktrees flag %q", arg)}
		default:
			if err := setWorktreeName(&options, arg); err != nil {
				return options, false, err
			}
		}
	}
	return options, false, nil
}

func setWorktreeName(options *worktreeCommandOptions, value string) error {
	name := strings.TrimSpace(value)
	if name == "" {
		return nil
	}
	if options.name != "" {
		return execUsageError{"worktree name was provided more than once"}
	}
	options.name = name
	return nil
}

func parseVerifyCommandArgs(args []string) (verifyCommandOptions, bool, error) {
	options := verifyCommandOptions{}
	for index := 0; index < len(args); index++ {
		arg := args[index]
		switch {
		case arg == "-h" || arg == "--help" || arg == "help":
			return options, true, nil
		case arg == "--json":
			options.json = true
		case arg == "-C" || arg == "--cwd":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			options.cwd = value
			index = next
		case strings.HasPrefix(arg, "--cwd="):
			options.cwd = strings.TrimSpace(strings.TrimPrefix(arg, "--cwd="))
		case arg == "--only":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			options.only = append(options.only, parseToolList(value)...)
			index = next
		case strings.HasPrefix(arg, "--only="):
			options.only = append(options.only, parseToolList(strings.TrimSpace(strings.TrimPrefix(arg, "--only=")))...)
		case arg == "--timeout-ms":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			timeoutMS, err := parsePositiveIntFlag("--timeout-ms", value)
			if err != nil {
				return options, false, err
			}
			options.timeoutMS = timeoutMS
			index = next
		case strings.HasPrefix(arg, "--timeout-ms="):
			timeoutMS, err := parsePositiveIntFlag("--timeout-ms", strings.TrimSpace(strings.TrimPrefix(arg, "--timeout-ms=")))
			if err != nil {
				return options, false, err
			}
			options.timeoutMS = timeoutMS
		case arg == "--attempts":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			attempts, err := parsePositiveIntFlag("--attempts", value)
			if err != nil {
				return options, false, err
			}
			options.attempts = attempts
			index = next
		case strings.HasPrefix(arg, "--attempts="):
			attempts, err := parsePositiveIntFlag("--attempts", strings.TrimSpace(strings.TrimPrefix(arg, "--attempts=")))
			if err != nil {
				return options, false, err
			}
			options.attempts = attempts
		case strings.HasPrefix(arg, "-"):
			return options, false, execUsageError{fmt.Sprintf("unknown verify flag %q", arg)}
		default:
			return options, false, execUsageError{fmt.Sprintf("unexpected verify argument %q", arg)}
		}
	}
	return options, false, nil
}

func parseChangesArgs(args []string, command string) (changesCommandOptions, bool, error) {
	options := changesCommandOptions{}
	for index := 0; index < len(args); index++ {
		arg := args[index]
		switch {
		case arg == "-h" || arg == "--help" || arg == "help":
			return options, true, nil
		case arg == "--json":
			options.json = true
		case arg == "--dry-run":
			options.dryRun = true
		case arg == "-C" || arg == "--cwd":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			options.cwd = value
			index = next
		case strings.HasPrefix(arg, "--cwd="):
			options.cwd = strings.TrimSpace(strings.TrimPrefix(arg, "--cwd="))
		case arg == "--base":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			options.baseRef = strings.TrimSpace(value)
			index = next
		case strings.HasPrefix(arg, "--base="):
			v := strings.TrimSpace(strings.TrimPrefix(arg, "--base="))
			if v == "" || flagValueLooksLikeOption(v) {
				return options, false, execUsageError{"--base requires a value"}
			}
			options.baseRef = v
		case arg == "-m" || arg == "--message":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			options.message = value
			options.hasMessage = true
			index = next
		case strings.HasPrefix(arg, "--message="):
			options.message = strings.TrimSpace(strings.TrimPrefix(arg, "--message="))
			options.hasMessage = true
		case arg == "--diff-bytes":
			value, next, err := nextFlagValue(args, index, arg)
			if err != nil {
				return options, false, err
			}
			maxDiffBytes, err := parsePositiveIntFlag("--diff-bytes", value)
			if err != nil {
				return options, false, err
			}
			options.maxDiffBytes = maxDiffBytes
			index = next
		case strings.HasPrefix(arg, "--diff-bytes="):
			maxDiffBytes, err := parsePositiveIntFlag("--diff-bytes", strings.TrimSpace(strings.TrimPrefix(arg, "--diff-bytes=")))
			if err != nil {
				return options, false, err
			}
			options.maxDiffBytes = maxDiffBytes
		case arg == "-a" || arg == "--auto":
			options.auto = true
		case strings.HasPrefix(arg, "-"):
			return options, false, execUsageError{fmt.Sprintf("unknown changes flag %q", arg)}
		default:
			return options, false, execUsageError{fmt.Sprintf("unexpected changes argument %q", arg)}
		}
	}
	if command != "commit" && (options.hasMessage || options.dryRun || options.auto) {
		return options, false, execUsageError{"--message, --dry-run, and --auto are only valid with `zero changes commit`"}
	}
	if command == "commit" && options.hasMessage && options.auto {
		return options, false, execUsageError{"cannot specify both --message and --auto"}
	}
	if command == "commit" && options.baseRef != "" {
		return options, false, execUsageError{"--base is only valid with `zero changes inspect`"}
	}
	return options, false, nil
}

func parsePositiveIntFlag(flag string, value string) (int, error) {
	trimmed := strings.TrimSpace(value)
	if trimmed == "" {
		return 0, execUsageError{flag + " requires a value"}
	}
	number, err := strconv.Atoi(trimmed)
	if err != nil || number <= 0 {
		return 0, execUsageError{fmt.Sprintf("invalid %s %q. Expected a positive integer.", flag, value)}
	}
	return number, nil
}

func redactWorktreeResult(result worktrees.Result) worktrees.Result {
	result.Name = redactCLIString(result.Name)
	result.Path = redactCLIString(result.Path)
	result.RepoRoot = redactCLIString(result.RepoRoot)
	result.SourceBranch = redactCLIString(result.SourceBranch)
	result.SourceCommit = redactCLIString(result.SourceCommit)
	return result
}

func redactVerifyReport(report verify.Report) verify.Report {
	report.Root = redactCLIString(report.Root)
	report.Results = append([]verify.Result{}, report.Results...)
	for index := range report.Results {
		report.Results[index].Stdout = redactCLIString(report.Results[index].Stdout)
		report.Results[index].Stderr = redactCLIString(report.Results[index].Stderr)
		report.Results[index].Error = redactCLIString(report.Results[index].Error)
		if report.Results[index].OutputSummary != nil {
			summary := *report.Results[index].OutputSummary
			summary.Lines = append([]string{}, summary.Lines...)
			for lineIndex := range summary.Lines {
				summary.Lines[lineIndex] = redactCLIString(summary.Lines[lineIndex])
			}
			report.Results[index].OutputSummary = &summary
		}
		if report.Results[index].TestSummary != nil {
			summary := *report.Results[index].TestSummary
			summary.Failures = append([]testrunner.Failure{}, summary.Failures...)
			for failureIndex := range summary.Failures {
				summary.Failures[failureIndex].Name = redactCLIString(summary.Failures[failureIndex].Name)
				summary.Failures[failureIndex].File = redactCLIString(summary.Failures[failureIndex].File)
				summary.Failures[failureIndex].Message = redactCLIString(summary.Failures[failureIndex].Message)
			}
			report.Results[index].TestSummary = &summary
		}
	}
	return report
}

func redactVerifyLoopReport(report selfverify.Report) selfverify.Report {
	report.Root = redactCLIString(report.Root)
	report.Error = redactCLIString(report.Error)
	for index := range report.Attempts {
		report.Attempts[index].Report = redactVerifyReport(report.Attempts[index].Report)
		if report.Attempts[index].Remediation != nil {
			remediation := *report.Attempts[index].Remediation
			remediation.StartedAt = redactCLIString(remediation.StartedAt)
			remediation.EndedAt = redactCLIString(remediation.EndedAt)
			remediation.Message = redactCLIString(remediation.Message)
			remediation.Error = redactCLIString(remediation.Error)
			report.Attempts[index].Remediation = &remediation
		}
	}
	return report
}

func redactChangeSummary(summary zerogit.ChangeSummary) zerogit.ChangeSummary {
	summary.Root = redactCLIString(summary.Root)
	summary.Base = redactCLIString(summary.Base)
	summary.Branch = redactCLIString(summary.Branch)
	summary.Commit = redactCLIString(summary.Commit)
	summary.DiffStat = redactCLIString(summary.DiffStat)
	summary.Diff = redactCLIString(summary.Diff)
	for index := range summary.Files {
		summary.Files[index].Path = redactCLIString(summary.Files[index].Path)
		summary.Files[index].Status = redactCLIString(summary.Files[index].Status)
	}
	return summary
}

func redactCommitResult(result zerogit.CommitResult) zerogit.CommitResult {
	result.Root = redactCLIString(result.Root)
	result.Message = redactCLIString(result.Message)
	result.CommitHash = redactCLIString(result.CommitHash)
	result.Before = redactChangeSummary(result.Before)
	return result
}

func redactCLIString(value string) string {
	// Keep ordinary paths visible; these commands report useful locations.
	// Central redaction still removes secret-looking tokens embedded in paths.
	return redaction.RedactString(value, redaction.Options{})
}

func formatWorktreeResult(result worktrees.Result) string {
	lines := []string{
		"Zero worktree ready",
		"name: " + result.Name,
		"path: " + result.Path,
		"repo: " + result.RepoRoot,
	}
	if result.SourceBranch != "" {
		lines = append(lines, "branch: "+result.SourceBranch)
	}
	if result.SourceCommit != "" {
		lines = append(lines, "commit: "+result.SourceCommit)
	}
	if result.Reused {
		lines = append(lines, "reused: true")
	}
	return strings.Join(lines, "\n")
}

func formatVerifyReport(report verify.Report) string {
	lines := []string{
		"Zero verification",
		"root: " + report.Root,
		fmt.Sprintf("summary: %d total, %d passed, %d failed, %d errors", report.Summary.Total, report.Summary.Passed, report.Summary.Failed, report.Summary.Errors),
	}
	if len(report.Results) == 0 {
		lines = append(lines, "  (no checks detected)")
		return strings.Join(lines, "\n")
	}
	for _, result := range report.Results {
		lines = append(lines, fmt.Sprintf("  [%s] %s - %s", result.Status, result.ID, strings.Join(result.Command, " ")))
		if result.TestSummary != nil {
			lines = append(lines, formatVerifyTestSummary(result.TestSummary))
			for _, failure := range result.TestSummary.Failures {
				if failure.Name == "" {
					continue
				}
				detail := failure.Name
				if failure.File != "" {
					detail += " at " + failure.File
				}
				lines = append(lines, "    failure: "+detail)
			}
		}
		if result.Error != "" {
			lines = append(lines, "    error: "+result.Error)
		}
	}
	return strings.Join(lines, "\n")
}

func formatVerifyTestSummary(summary *testrunner.Summary) string {
	line := fmt.Sprintf("    tests: %d total, %d passed, %d failed", summary.Total, summary.Passed, summary.Failed)
	if summary.Skipped > 0 {
		line += fmt.Sprintf(", %d skipped", summary.Skipped)
	}
	return line
}

func formatVerifyLoopReport(report selfverify.Report) string {
	lines := []string{
		"Zero self-verification",
	}
	if report.Root != "" {
		lines = append(lines, "root: "+report.Root)
	}
	lines = append(lines,
		fmt.Sprintf("attempts: %d", len(report.Attempts)),
		"stop: "+string(report.StopReason),
		fmt.Sprintf("summary: %d total, %d passed, %d failed, %d errors", report.Summary.Total, report.Summary.Passed, report.Summary.Failed, report.Summary.Errors),
	)
	for _, attempt := range report.Attempts {
		status := "failed"
		if attempt.Report.OK {
			status = "passed"
		}
		lines = append(lines, fmt.Sprintf("  attempt %d: %s", attempt.Number, status))
		if attempt.Remediation != nil {
			lines = append(lines, "    remediation: "+formatRemediation(*attempt.Remediation))
		}
	}
	if report.Error != "" {
		lines = append(lines, "error: "+report.Error)
	}
	return strings.Join(lines, "\n")
}

func formatRemediation(remediation selfverify.Remediation) string {
	status := "not applied"
	if remediation.Applied {
		status = "applied"
	}
	details := []string{status}
	if remediation.Message != "" {
		details = append(details, remediation.Message)
	}
	if remediation.Error != "" {
		details = append(details, "error: "+remediation.Error)
	}
	return strings.Join(details, " - ")
}

func formatChangeSummary(summary zerogit.ChangeSummary) string {
	lines := []string{
		"Zero changes",
		"root: " + summary.Root,
		fmt.Sprintf("files: %d changed", len(summary.Files)),
	}
	if summary.Branch != "" {
		lines = append(lines, "branch: "+summary.Branch)
	}
	if summary.Base != "" {
		lines = append(lines, "base: "+summary.Base)
	}
	if summary.Commit != "" {
		lines = append(lines, "commit: "+summary.Commit)
	}
	if summary.Clean {
		lines = append(lines, "clean: true")
		return strings.Join(lines, "\n")
	}
	for _, file := range summary.Files {
		lines = append(lines, fmt.Sprintf("  [%s] %s", file.Status, file.Path))
	}
	return strings.Join(lines, "\n")
}

func formatCommitResult(result zerogit.CommitResult) string {
	lines := []string{
		"Zero changes commit",
		"root: " + result.Root,
		"message: " + result.Message,
		fmt.Sprintf("dry-run: %t", result.DryRun),
		fmt.Sprintf("committed: %t", result.Committed),
		fmt.Sprintf("files: %d changed", len(result.Before.Files)),
	}
	if result.CommitHash != "" {
		lines = append(lines, "commit: "+result.CommitHash)
	}
	return strings.Join(lines, "\n")
}

func writeWorktreesHelp(w io.Writer) error {
	_, err := fmt.Fprint(w, `Usage:
  zero worktrees prepare [flags] [name]

Prepares an isolated git worktree for a Zero task.

Flags:
      --name <name>       Worktree name; defaults to a timestamped task name
      --dir <path>        Base directory for Zero worktrees
  -C, --cwd <path>        Source repository directory
      --json              Print JSON output
  -h, --help              Show this help
`)
	return err
}

func writeVerifyHelp(w io.Writer) error {
	_, err := fmt.Fprint(w, `Usage:
  zero verify [flags]

Detects and runs local verification checks for the workspace.

Flags:
  -C, --cwd <path>        Workspace directory
      --only <ids>        Run only matching check ids
      --timeout-ms <n>    Per-check timeout in milliseconds
      --attempts <n>      Run a bounded self-verification loop
      --json              Print JSON output
  -h, --help              Show this help
`)
	return err
}

func writeChangesHelp(w io.Writer) error {
	_, err := fmt.Fprint(w, `Usage:
  zero changes inspect [flags]
  zero changes commit [flags]

Inspects local git changes and optionally creates a commit.

Flags:
  -C, --cwd <path>        Workspace directory
      --base <ref>        Diff against <ref>...HEAD instead of the working tree
      --diff-bytes <n>    Maximum diff bytes to include
  -m, --message <text>    Commit message for `+"`zero changes commit`"+`
  -a, --auto              Auto-generate commit message using LLM (use --dry-run to preview)
      --dry-run           Preview commit metadata without mutating git state
      --json              Print JSON output
  -h, --help              Show this help
`)
	return err
}

func generateAutoCommitMessage(ctx context.Context, provider zeroruntime.Provider, model string, summary zerogit.ChangeSummary) (string, error) {
	var promptBuilder strings.Builder
	promptBuilder.WriteString("Analyze the following git diff and generate a concise, conventional commit message.\n")
	promptBuilder.WriteString("The commit message subject line must be 72 characters or fewer, starting with a conventional commit type (e.g., feat, fix, docs, style, refactor, test, chore) followed by a colon and space, and a lowercase description.\n")
	promptBuilder.WriteString("You may optionally include a blank line and a bulleted list of changes for the body if there are multiple files or complex changes.\n")
	promptBuilder.WriteString("Output ONLY the raw commit message text. Do not wrap the message in markdown code block fence, do not include quotes or any introduction/explanation.\n\n")
	promptBuilder.WriteString("Git Diff:\n")
	promptBuilder.WriteString(summary.Diff)

	request := zeroruntime.CompletionRequest{
		Messages: []zeroruntime.Message{
			{Role: zeroruntime.MessageRoleUser, Content: promptBuilder.String()},
		},
	}
	stream, err := provider.StreamCompletion(ctx, request)
	if err != nil {
		return "", err
	}
	collected := zeroruntime.CollectStream(ctx, stream)
	if collected.Error != "" {
		return "", fmt.Errorf("%s", collected.Error)
	}

	msg := strings.TrimSpace(collected.Text)
	if strings.HasPrefix(msg, "```") {
		if idx := strings.Index(msg, "\n"); idx != -1 {
			msg = msg[idx+1:]
		}
	}
	msg = strings.TrimSuffix(msg, "```")
	msg = strings.TrimSpace(msg)
	if msg == "" {
		return "", fmt.Errorf("provider returned empty commit message")
	}
	return msg, nil
}