package tools

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

	"forge.lclr.dev/AI/xdebug-mcp/internal/cache"
	"forge.lclr.dev/AI/xdebug-mcp/internal/cachegrind"
)

// loadProfile returns a parsed Profile from cache or by parsing the file.
func loadProfile(filePath string, c *cache.Cache) (*cachegrind.Profile, error) {
	abs, err := filepath.Abs(filePath)
	if err != nil {
		return nil, fmt.Errorf("resolve path %s: %w", filePath, err)
	}
	info, err := os.Stat(abs)
	if err != nil {
		return nil, fmt.Errorf("file not found: %s", abs)
	}
	if p, ok := c.Get(abs, info.ModTime()); ok {
		return p, nil
	}
	p, err := cachegrind.ParseFile(abs)
	if err != nil {
		return nil, err
	}
	c.Set(abs, p, info.ModTime())
	return p, nil
}

// findFunctions returns functions matching name (exact first, then contains).
// Returns a non-empty errMsg if nothing is found.
func findFunctions(p *cachegrind.Profile, name string) ([]*cachegrind.Function, string) {
	if fns, ok := p.ByName[name]; ok {
		return fns, ""
	}
	var matches []*cachegrind.Function
	for _, fn := range p.Functions {
		if strings.Contains(fn.Name, name) {
			matches = append(matches, fn)
		}
	}
	if len(matches) == 0 {
		return nil, fmt.Sprintf("function %q not found in profile (no exact or contains match)", name)
	}
	return matches, ""
}

// sortedByTime returns a copy of fns sorted by Costs[0] descending.
func sortedByTime(fns []*cachegrind.Function) []*cachegrind.Function {
	sorted := make([]*cachegrind.Function, len(fns))
	copy(sorted, fns)
	sort.Slice(sorted, func(i, j int) bool {
		ci, cj := int64(0), int64(0)
		if len(sorted[i].Costs) > 0 {
			ci = sorted[i].Costs[0]
		}
		if len(sorted[j].Costs) > 0 {
			cj = sorted[j].Costs[0]
		}
		return ci > cj
	})
	return sorted
}

// formatCosts formats a cost slice as "Event=value  Event=value".
func formatCosts(costs []int64, events []string) string {
	parts := make([]string, 0, len(events))
	for i, ev := range events {
		if i < len(costs) {
			parts = append(parts, fmt.Sprintf("%s=%d", ev, costs[i]))
		}
	}
	return strings.Join(parts, "  ")
}