package main

import (
	"fmt"
	"os"
	"path"
	"text/template"

	"github.com/pelletier/go-toml"
)

// Config contains site configuration.
type Config struct {
	Title     string            `toml:"title"` // site title
	URLs      []string          `toml:"urls"`  // site URLs
	Feeds     map[string]string `toml:"feeds"` // site feeds
	Tasks     map[string]*Task  `toml:"tasks"` // site tasks
	Templates *Templates        `toml:"-"`     // site templates
}

// Task represents a site build task.
type Task struct {
	Input       string `toml:"input"`       // input file extension
	Output      string `toml:"output"`      // output file extension
	Template    string `toml:"template"`    // template file extension
	PostProcess string `toml:"postprocess"` // postprocess directive
	Destination string `toml:"destination"` // destination directory
	postProcess Format
}

func (t Task) Format(p *Page) (string, []byte) {
	if t.postProcess == nil {
		return path.Join(p.Path, "index"+t.Output), []byte(p.Content)
	}
	return t.postProcess.Format(p)
}

// LoadConfig loads the configuration from the provided path.
func LoadConfig(path string) (*Config, error) {
	c := new(Config)
	f, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	if err := toml.NewDecoder(f).Decode(c); err != nil {
		return nil, err
	}

	// Add default task
	// The toml library overwrites the map, so add default values after parsing
	if _, ok := c.Tasks["gemini"]; !ok {
		c.Tasks["gemini"] = &Task{
			Input:       ".gmi",
			Output:      ".gmi",
			Template:    ".gmi",
			Destination: "public",
		}
	}

	for _, task := range c.Tasks {
		switch task.PostProcess {
		case "":
			continue
		case "geminiToHTML":
			task.postProcess = GeminiToHTML(c)
		default:
			return nil, fmt.Errorf("unrecognized postprocess directive %q", task.PostProcess)
		}
	}

	return c, nil
}

// LoadTemplates loads templates from the provided path.
func (c *Config) LoadTemplates(path string) error {
	// Site contains site metadata passed to templates
	type Site struct {
		Title string
		URLs  []string
	}

	// Load templates
	c.Templates = NewTemplates()
	c.Templates.Funcs(template.FuncMap{
		"site": func() Site {
			return Site{
				Title: c.Title,
				URLs:  c.URLs,
			}
		},
	})
	c.Templates.LoadDefault()
	return c.Templates.Load(path)
}