package app

import (
	"bytes"
	"fmt"
	"strings"

	"github.com/helmfile/helmfile/pkg/environment"
	"github.com/helmfile/helmfile/pkg/state"
	"github.com/helmfile/helmfile/pkg/tmpl"
)

func prependLineNumbers(text string) string {
	buf := bytes.NewBufferString("")
	lines := strings.Split(text, "\n")
	for i, line := range lines {
		buf.WriteString(fmt.Sprintf("%2d: %s\n", i, line))
	}
	return buf.String()
}

type RenderOpts struct {
}

func (r *desiredStateLoader) renderTemplatesToYaml(baseDir, filename string, content []byte) (*bytes.Buffer, error) {
	env := &environment.Environment{Name: r.env, Values: map[string]any(nil)}

	return r.renderTemplatesToYamlWithEnv(baseDir, filename, content, env, nil)
}

func (r *desiredStateLoader) renderTemplatesToYamlWithEnv(baseDir, filename string, content []byte, inherited, overrode *environment.Environment) (*bytes.Buffer, error) {
	return r.twoPassRenderTemplateToYaml(inherited, overrode, baseDir, filename, content)
}

func (r *desiredStateLoader) twoPassRenderTemplateToYaml(inherited, overrode *environment.Environment, baseDir, filename string, content []byte) (*bytes.Buffer, error) {
	// try a first pass render. This will always succeed, but can produce a limited env
	var phase string
	r.logger.Debugf("%srendering starting for \"%s\": inherited=%v, overrode=%v", phase, filename, inherited, overrode)

	initEnv, err := inherited.Merge(nil)
	if err != nil {
		return nil, err
	}

	var (
		renderingPhase string
		finalEnv       *environment.Environment
		vals           map[string]any
	)

	finalEnv, err = initEnv.Merge(overrode)
	if err != nil {
		return nil, err
	}

	vals, err = finalEnv.GetMergedValues()
	if err != nil {
		return nil, err
	}

	tmplData := state.NewEnvironmentTemplateData(*finalEnv, r.namespace, vals)
	renderer := tmpl.NewFileRenderer(r.fs, baseDir, tmplData)
	yamlBuf, err := renderer.RenderTemplateContentToBuffer(content)
	if err != nil {
		r.logger.Debugf("%srendering failed, input of \"%s\":\n%s", renderingPhase, filename, prependLineNumbers(string(content)))
		return nil, err
	}
	r.logger.Debugf("%srendering result of \"%s\":\n%s", renderingPhase, filename, prependLineNumbers(yamlBuf.String()))
	return yamlBuf, nil
}