// report parses life report JSON and
package report

import (
	"encoding/json"
	"fmt"
	"html/template"
	"os"
	"path"
	"strconv"
	"strings"
)

type (
	// Report represents a life report. It contains summaries and lists on
	// various areas of a given person's life for the given time period --
	// in this case, a month.
	Report struct {
		File     string
		Num      int
		Month    string
		Year     int       `json:"year"`
		Summary  string    `json:"summary"`
		Sections []Section `json:"sections"`
	}

	// Section represents an area of life to report on. This contains a
	// title to describe the area, a set of paragraphs representing a
	// summary, and a set of details representing a list of more specific
	// items.
	Section struct {
		Title   string          `json:"title"`
		Summary []template.HTML `json:"summary"`
		Details []template.HTML `json:"details"`
		Rank    []template.HTML `json:"rank"`
	}
)

// ParseReport takes a file and generates a life report from it. It
// assumes the file is named in the format NNN-month.json where NNN is the
// number of the report, usually named with leading zeroes so they're
// ordered correctly on your filesystem.
func ParseReport(f *os.File) (*Report, error) {
	var err error
	r := Report{}

	// Parse JSON into a Report
	jsonParser := json.NewDecoder(f)
	if err = jsonParser.Decode(&r); err != nil {
		return nil, err
	}

	// Determine report number and month from filename in the format
	// NNN-month.json
	r.File = path.Base(f.Name())
	fd := strings.Split(r.File[:strings.Index(r.File, ".json")], "-")
	if len(fd) >= 2 {
		r.Num, err = strconv.Atoi(fd[0])
		if err != nil {
			fmt.Fprintf(os.Stderr, "Unable to parse report number: %v\n", err)
			r.Num = 1
		}
		r.Month = strings.Title(fd[1])
	} else {
		r.Num = 1
		r.Month = "First"
	}

	return &r, nil
}

// ByNum implements sort.Interface for []Report based on the Num field.
type ByNum []Report

func (n ByNum) Len() int           { return len(n) }
func (n ByNum) Swap(i, j int)      { n[i], n[j] = n[j], n[i] }
func (n ByNum) Less(i, j int) bool { return n[i].Num < n[j].Num }