package doctor

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/steveyegge/gastown/internal/beads"
	"github.com/steveyegge/gastown/internal/config"
)

// RoutesCheck verifies that beads routing is properly configured.
// It checks that routes.jsonl exists, all rigs have routing entries,
// and all routes point to valid locations.
type RoutesCheck struct {
	FixableCheck
}

// NewRoutesCheck creates a new routes configuration check.
func NewRoutesCheck() *RoutesCheck {
	return &RoutesCheck{
		FixableCheck: FixableCheck{
			BaseCheck: BaseCheck{
				CheckName:        "routes-config",
				CheckDescription: "Check beads routing configuration",
				CheckCategory:    CategoryConfig,
			},
		},
	}
}

// Run checks the beads routing configuration.
func (c *RoutesCheck) Run(ctx *CheckContext) *CheckResult {
	beadsDir := filepath.Join(ctx.TownRoot, ".beads")
	routesPath := filepath.Join(beadsDir, beads.RoutesFileName)

	// Check if .beads directory exists
	if _, err := os.Stat(beadsDir); os.IsNotExist(err) {
		return &CheckResult{
			Name:    c.Name(),
			Status:  StatusWarning,
			Message: "No .beads directory at town root",
			FixHint: "Run 'bd init' to initialize beads",
		}
	}

	// Check if routes.jsonl exists
	if _, err := os.Stat(routesPath); os.IsNotExist(err) {
		return &CheckResult{
			Name:    c.Name(),
			Status:  StatusWarning,
			Message: "No routes.jsonl file (prefix routing not configured)",
			FixHint: "Run 'gt doctor --fix' to create routes.jsonl",
		}
	}

	// Load existing routes
	routes, err := beads.LoadRoutes(beadsDir)
	if err != nil {
		return &CheckResult{
			Name:    c.Name(),
			Status:  StatusError,
			Message: fmt.Sprintf("Failed to load routes.jsonl: %v", err),
		}
	}

	// Build maps of existing routes
	routeByPrefix := make(map[string]string) // prefix -> path
	routeByPath := make(map[string]string)   // path -> prefix
	for _, r := range routes {
		routeByPrefix[r.Prefix] = r.Path
		routeByPath[r.Path] = r.Prefix
	}

	// Load rigs registry
	rigsPath := filepath.Join(ctx.TownRoot, "mayor", "rigs.json")
	rigsConfig, err := config.LoadRigsConfig(rigsPath)
	if err != nil {
		// No rigs config is fine - just check existing routes are valid
		return c.checkRoutesValid(ctx, routes)
	}

	var details []string
	var missingRigs []string
	var invalidRoutes []string

	// Check each rig has a route (by path, not just prefix from rigs.json)
	for rigName, rigEntry := range rigsConfig.Rigs {
		expectedPath := rigName + "/mayor/rig"

		// Check if there's already a route for this rig (by path)
		if _, hasRoute := routeByPath[expectedPath]; hasRoute {
			// Rig already has a route, even if prefix differs from rigs.json
			continue
		}

		// No route by path - check by prefix from rigs.json
		prefix := ""
		if rigEntry.BeadsConfig != nil && rigEntry.BeadsConfig.Prefix != "" {
			prefix = rigEntry.BeadsConfig.Prefix + "-"
		}

		if prefix != "" {
			if _, found := routeByPrefix[prefix]; !found {
				missingRigs = append(missingRigs, rigName)
				details = append(details, fmt.Sprintf("Rig '%s' (prefix: %s) has no routing entry", rigName, prefix))
			}
		}
	}

	// Check each route points to a valid location
	for _, r := range routes {
		rigPath := filepath.Join(ctx.TownRoot, r.Path)
		beadsPath := filepath.Join(rigPath, ".beads")

		// Special case: "." path is town root, already checked
		if r.Path == "." {
			continue
		}

		// Check if the path exists
		if _, err := os.Stat(rigPath); os.IsNotExist(err) {
			invalidRoutes = append(invalidRoutes, r.Prefix)
			details = append(details, fmt.Sprintf("Route %s -> %s: path does not exist", r.Prefix, r.Path))
			continue
		}

		// Check if .beads directory exists (or redirect file)
		redirectPath := filepath.Join(beadsPath, "redirect")
		_, beadsErr := os.Stat(beadsPath)
		_, redirectErr := os.Stat(redirectPath)

		if os.IsNotExist(beadsErr) && os.IsNotExist(redirectErr) {
			invalidRoutes = append(invalidRoutes, r.Prefix)
			details = append(details, fmt.Sprintf("Route %s -> %s: no .beads directory", r.Prefix, r.Path))
		}
	}

	// Determine result
	if len(missingRigs) > 0 || len(invalidRoutes) > 0 {
		status := StatusWarning
		message := ""

		if len(missingRigs) > 0 && len(invalidRoutes) > 0 {
			message = fmt.Sprintf("%d rig(s) missing routes, %d invalid route(s)", len(missingRigs), len(invalidRoutes))
		} else if len(missingRigs) > 0 {
			message = fmt.Sprintf("%d rig(s) missing routing entries", len(missingRigs))
		} else {
			message = fmt.Sprintf("%d invalid route(s) in routes.jsonl", len(invalidRoutes))
		}

		return &CheckResult{
			Name:    c.Name(),
			Status:  status,
			Message: message,
			Details: details,
			FixHint: "Run 'gt doctor --fix' to add missing routes",
		}
	}

	return &CheckResult{
		Name:    c.Name(),
		Status:  StatusOK,
		Message: fmt.Sprintf("Routes configured correctly (%d routes)", len(routes)),
	}
}

// checkRoutesValid checks that existing routes point to valid locations.
func (c *RoutesCheck) checkRoutesValid(ctx *CheckContext, routes []beads.Route) *CheckResult {
	var details []string
	var invalidCount int

	for _, r := range routes {
		if r.Path == "." {
			continue // Town root is valid
		}

		rigPath := filepath.Join(ctx.TownRoot, r.Path)
		if _, err := os.Stat(rigPath); os.IsNotExist(err) {
			invalidCount++
			details = append(details, fmt.Sprintf("Route %s -> %s: path does not exist", r.Prefix, r.Path))
		}
	}

	if invalidCount > 0 {
		return &CheckResult{
			Name:    c.Name(),
			Status:  StatusWarning,
			Message: fmt.Sprintf("%d invalid route(s) in routes.jsonl", invalidCount),
			Details: details,
			FixHint: "Remove invalid routes or recreate the missing rigs",
		}
	}

	return &CheckResult{
		Name:    c.Name(),
		Status:  StatusOK,
		Message: fmt.Sprintf("Routes configured correctly (%d routes)", len(routes)),
	}
}

// Fix attempts to add missing routing entries.
func (c *RoutesCheck) Fix(ctx *CheckContext) error {
	beadsDir := filepath.Join(ctx.TownRoot, ".beads")

	// Ensure .beads directory exists
	if _, err := os.Stat(beadsDir); os.IsNotExist(err) {
		return fmt.Errorf(".beads directory does not exist; run 'bd init' first")
	}

	// Load existing routes
	routes, err := beads.LoadRoutes(beadsDir)
	if err != nil {
		routes = []beads.Route{} // Start fresh if can't load
	}

	// Build map of existing prefixes
	routeMap := make(map[string]bool)
	for _, r := range routes {
		routeMap[r.Prefix] = true
	}

	// Load rigs registry
	rigsPath := filepath.Join(ctx.TownRoot, "mayor", "rigs.json")
	rigsConfig, err := config.LoadRigsConfig(rigsPath)
	if err != nil {
		// No rigs config, nothing to fix
		return nil
	}

	// Add missing routes for each rig
	modified := false
	for rigName, rigEntry := range rigsConfig.Rigs {
		prefix := ""
		if rigEntry.BeadsConfig != nil && rigEntry.BeadsConfig.Prefix != "" {
			prefix = rigEntry.BeadsConfig.Prefix + "-"
		}

		if prefix != "" && !routeMap[prefix] {
			// Verify the rig path exists before adding
			rigPath := filepath.Join(ctx.TownRoot, rigName, "mayor", "rig")
			if _, err := os.Stat(rigPath); err == nil {
				route := beads.Route{
					Prefix: prefix,
					Path:   rigName + "/mayor/rig",
				}
				routes = append(routes, route)
				routeMap[prefix] = true
				modified = true
			}
		}
	}

	if modified {
		return beads.WriteRoutes(beadsDir, routes)
	}

	return nil
}